Assembling fixture



Oct. 30, 1951 B. P. GIRARD ETAL 2,573,432

ASSEMBLING FIXTURE 3 Sheets-Sheet 2 Filed July 23, 1946 llllllllIHIIHIIIIHH H'lll INVENTORS B. RG/RARD BAR/1E TSCH ATTORNEY Oct. 30'.1951 B. P. GIRARD ETAL 2,573,432

ASSEMBLIING FIXTURE 7 Filed July 23, 1946 3 sheets-sheet s 44 FIG. 7 4345 42 [45 ll] illlllli i) A T TORNEY Patented Oct. 30, 1951 P-A l emOIFFIICET AS SEMBLI'NG FIXTURE:

lfieorporatedfNew York;

New York NPYi; arcorporation' of ApplicatiomJilly 23,4946, SerialNo,685,728

1 GCliiiihsr (01 This invention relates to. assemblingmitturess and morepartieuiarly to fixtures'for assembling? potentiometer, cardsan'd"associatefelements in potentiometer housings? Thisinventionisi"related 'in generalftoassem 5' bling potentiometer. cards,insulezting' gstrips Janet i slip rin'gs in multiple'rgroove typecylindriealpotentiometer'housings; The potentiometer"hous-'ingsmayfhaveioneor more annular grooves pro: vided". therein forreceiving: a: fixed number; of elements:- requir'edito make: up a singlepoten-i' tiometerum'ti Iii'one "partidular type: ofpote'n tiom'etreachemiul'arfgr'oove. of'iheTpotentidme ter-housinghas"assembled'thereintagroupiot'e1e= ments; comprising an outer insulatingring, at. potentiometer card, tworintermediate insulating: rings," aslip :ring "and"aminsulatefbridge mem ber: Thev potentiometeri cardi'hesits beginning: turna'ntFitsi en'dtturn marked'tand' is positioned" in*the'housing'so thatonepffthe'marked turns is "directlyoppositescribemarksprovidedbn the: face .of the'respective partition.whic'hiorms .the. particular-annular'groove'involvedi The "potentiometercard'antl thesl'ipring must? havetheir 'conta'ctihg'surfacesinfthesame'wplaine; which plane *must'be slightly above 'th'eia'ce of .1 thehousing: while: thewariou's -insu1atingTriri'gs'" must be positioned?substantially "below thisz'con tacti'ngplanes The 'brideemustfbepcsitionedjn linewith'ithe 0111761 insulating ring ,1 ain'd'ihaveit's 1 topt'face extendingiaboveithe .contactiiig plblne of the"potentiometer: card; so that 'it will" lift the V potentiometer "brush"offltne'-card"wlien" itis moving"fr'om the end'i of"'the"cardto thebeginning; thereof orvice vers'a;

One proposed'method ot assembling the various. elementsinto' the annulargroove was by ifancLfl in whichtcas'e each" element was partially,positionecl'inithe groovein'itsproper position, andf' thenth'eentirefgroup' Wetsiforced'into thezgroove. Inforcin'gthe groupoi"el'e'ments intoitheegroovey. relative movement betweentheindividiialfielments resuitedjland when'it'was necessary toadjust'only 'one'pf the"elements:vsuchladjiistnient usualli disturbed theother "elements.

When any movement ocourredbetween 'the'potentiometer'cardiandfthevarious insultttingrings,1 it usually-produced e'series' 'of-1oo'setiirnsion the: potentiometer "card'twhiehlseriousiy j efiectedftfienelectriealcheracteristiesof tiirardor broke or" 50' 2.loosenedi'zthelea'ds 'secure'dtothe beginning andendi'turns':o'fi'the"card: Inedditibn, it"wa's'very difiicult t6 1position" each' individual element at":- its proper"elevationwithre'spect tfieach other and'to the-face of thepotentiometer'housing;

h'andess'em'bly'of'the'intiividual elements" within'ihefammlargrooveproved' to: bee? very tediiiusii'andJtime=c0nsumingoperation:Fiirther more; Many units'w'ere unsatisfactory'becau'se"ofabove-described. defects prod-needby'sucifassem blyl An obi 'e'ctof""the'inventib'n is'ii'tofprovid'i new: andifimproved' assemblingfixtures;

Another object of "the invention is to provide an assemblytfiiiturefor-assemblingivariws e1'e-'- ments required' to" make up'acyl'ihdricatpo tenti'ometer. a. p

In accordance withla specifieiembodiinenfioi the invention-.there.isprovidedmeansifor effect ingea loose pre-assembl'y offtheivariouselements toberassembledfin the groove. of .a potentiometer housing,means for t clamping: the elments' tightl'i together as a compositeunitin theifiiitiire-and meansior transferring-4 vthe unit from v thefiiiture 'to'the potentiometer hbusing dfir'ing.which trans fer no:relative -movement occurs between the. in-i dividualielementsofthe-unit;

Awclear. .understandi'ngpf the invention. maybe.

hadv from the. following. detailed? description. of-

formingLaspeei-fic embodiment ofethe invention;

Fig, 2 is a vertical, sectionalview-tal zen along, line 2.-2 of Fig-:-1; t

Fig: 3 is :an enlarged-,tfragmentary, verticaiwiew ofwa pertion of the:fixture :ShOWn in:Fig.-- 1,: and havingiportions .thereofabroken: awayto illu'straite- ,,someiofitheiintemalzstructure;

Fig-.14 is" a fragmentary; verticali'rig hwhend viewof a portion 1 oitheapparatusshown in Fig: 1 2 j Fig? 5- is ai"-fi"agmentaryi frontverticaivievv of a. portion of the apparatiisshown*inFig 1 Fig: 6* is ahorizontaL seetiiinal view" taken aldngiline BLSbfFii fZi" Fig, 7 isanienlar'ged; iregmentem'veritieaisectionaIifviewioiiaportiowofltne:a'pperatiis:

elements to be assembled together in a potentiometer housing;

Fig. 9 is a fragmentary, vertical sectional view showing the variouselements of Fig. 8 positioned in the apparatus shown in Figs. 1 and 2;

Fig. is a fragmentary, vertical sectional view taken along line |6|6 ofFig. 5;

Fig. 11 shows the assembling fixture inverted and positioned on apotentiometer housing, and

Fig. 12 shows the position of the elements in the potentiometer housingafter they have been transferred from the fixture.

Referring now to the .drawings, particularly Fig. 2, there is shown acylindrical support 28 having a bore 2| and a counterbore 22 adjacentand supporting an assembling fixture 23. The support 2|] serves to holdthe assembling fixture 23 in a substantially stationary position while apotentiometer card and its associated strip-like elements, hereinafterto be described, are assembled in the fixture 23. prises a ring 24having a bore 25 adjacent to its upper face, a counterbore 26 adjacentto its lower ring 24 adjacent to the counterbore 26 and is provided withan integral flange 32, the periphery of which is substantially flushwith the periphery of the ring 24. The flange 32 is positioned againstthe bottom face of the annular ring 24 and secured thereto by aplurality of screws 3333, and is provided with four arcuate slots 35-35spaced equidistantly around the periphery 34 of the body portion 3|(Fig. 6). The inner wall of the slots 3535 is vertically aligned withthe periphery 34 and the outer wall of the slots is vertically alignedwith the bore 25 of the ring 24.

An ejector ring 36 is slidably positioned around the body portion 3| andis provided with four arouate-shaped legs 3131 slidably positioned inthe arcuate slots 3535 provided in the flange 32. The flange 32 is widerthan the bottom face of the flange 32 and it extends beyond thecounterbore 26 and thereby provides an annular shoulder 38 similar tothe shoulder 21 provided in the ring 24. The ring 36 is provided with anannular flange 40, the periphery of which slidably engages thecounterbore 26 of the ring 24. Since the flange is free to slide in thecounterbore 26 between the shoulder 21 and the shoulder 38, the travelof the ring 36 is fixed by these shoulders. The upper face of the ring36 is provided with an outer groove 4| and an inner groove 42 which .15to the upper face of the support for receiving 4 municates with thebottom of a horizontal arcuate slot 54 cut in the periphery of the ring24 so that a substantially thin wall section exists at the sight hole53, whereby the surface 45 at the points 46 and 41 may be easily viewedtherethrough. An elongated sight hole 55 (Fig. 5) is provided at thebottom of a tapered aperture 56 also provided in the periphery of theannular ring 24 (Fig.2). A thin wall section 51 remains above theelongated sight hole 56 and has an index marked 58 centrally scribedthereon. An index mark 66 (Fig. 12) is scribed across the bottom wall ofthe sight hole 55 provided in the tapered aperture 56 directly in linewith the index mark 58..

A resilient clamping ring 62 (Fig. 2) is positioned on the upper face ofthe base 3|] and is provided with a plurality of substantially circularapertures 6363 adjacent to its outer peri hery The fixture 23 com:

form an outer annular ring 43 between the periphery of the ring 36 andthe groove 4] and an inner annular ring 44 between the grooves 4| and 42(Fig. '7). The bottoms of the grooves 4| and 42 are in the same planewhich plane is indicated by the surface marked 45 (Fig. 7) The annularrings 43 and 44 are cut away at points 46, 41, 48 and 5|), as shown inFig. l, in which case only the surface 45 is present at these points.

At the point 58 a recess 5| (Fig. 3) is out in the ring 36 and has itsbottom 52 substantially below the bottom 45 of the annular grooves 4|and 42.

64. The apertures 63-63 break through the inner periphery 65 of the baseof the ring 62 and together with a saw cut 66 provided across the ring62 serve to make the ring 62 resilient about its outer periphery 64. Thering 62 has a tapered bore 61 which tapers outwardly from the inner baseperiphery 64 to a point on the top face thereof adjacent to the outerperiphery 64 of the ring. A cam 68 is provided with a tapered peripherywhich slidably engages the tapered surface 66 provided in the clampingring 62 and is provided with a bore 16 and a large counterbore 1|. Aclamping bolt 12 is rotatably positioned in the bore 10 of the cam 61and has provided on the upper end thereof a large circular head 13 whichis positioned in the counterbore I. The head 13 is provided with ahexagonal aperture 14 for receiving a suitable socket wrench (not shown)which may be used to impart a rotary movement to the bolt 12. The lowerend of the bolt 12 is threadedly mounted in a tapped bore 15 provided inthe body portion 3| of the base member 36. A compression spring 16 ispositioned over the bolt 12 between a shoulder 18 formed by acounterbore 11 provided in the body portion 3| and the tapped bore 15and the under surface of the cam 61 and serves to urge the cam plateupwardly as the bolt 12 is backed out of the tapped bore 15. An annularassembling groove 19 is formed between the bore 25 of the ring 24 andthe outer periphery 64 of the resilient ring 62, in which the variouspotentiometer groove elements shown in Fig. 3 are to be assembled ashereinafter to be described. The groove 19 is variable in width due tothe fact that the periphcry 64 of the ring 62 may be expanded by drawingthe cam plate 68 downwardly by turning the bolt 12 in a clockwisedirection. As the cam plate is drawn downwardly against the action ofthe spring 16, its tapered periphery serves to expand the ring 62 anddecrease the width of the groove 19. When the cam plate 68 is positionedsubstantially as shown in Fig. 2, the resilient ring is in its retractedposition, that is, its periphery 64 is not flush with the periphery 34of the body portion 3|, whereby the groove 19 is at its maximum width,and the fixture 23 is in its normal element receiving position.

A pin is rigidly secured in a vertical bore 8| provided in the bodyportion 3| of the base member 30 and slidably engages a verticallyaligned bore 82 provided in the cam 68. The pin 88 serves to prevent anyrotary movement of the cam 68 when the bolt 12 is being rotated. A pin83 is rigidlysecured in a bore 84 provided in the base 25, and slidablyengages the vertically aligned bore e: provided "in the body portion QIor the hose member 30. The pin 83 serves to maintain the fixture 23 in astationary position during the assembly operation to behereinafterjdescribed.

Fig. 1 1 shows a portion *of a potentiometer housing -90 which isprovided with a plurality of annular grooves 9-1-9 I, in which are to beassembled a potentiometer card and associated elements shown in Fig. 8.'Since the same prob lemsarise in-assembling elements similar to thoseshown in Fig. 8 in each of the annular grooves w en of the potentiometerhousing "90, the assembly'of the elements in the outer groove "9| onlywill 'be discussed. The various elements which are to be assembled "inthe 'outer groove SI of the housinggm-as shown in Fig-'8, comprise ametallic slip ring 95 having an offset end 96 which overlaps theoppositeend of the'ring'and a very smooth, contacting surface 9 1, asuitable lead '98 secured to the slip ring adjacent to the dfiset end96, anin'sulating ring I '0? sufficient length to completely surroundthe slip ring 95 with the-exception-of the oifsetend 96, asecondinsulating ring I01 of-sufiicient l'ength to completely surround theinsulating ring I00 and having its open end diametrically opposite theopen end-of the ring 1330, a "potentiometer card I02 having -'acontacting surface I03, its beginning turn marked as indicated at-'I-0'4 an'd leads I05-I 05 secured to the beginningand end turns of thecard, an outer insulating ring I06 of suffioient length to completelysurround the potentiometer card I02 except for that portion of the cardbetween the leads II'. .iI05,-a bridge member I01 having acontactingsurface 103 and an insulating envelope H0 in which the bridge member I0? is placed before being positioned against the potentiometer card I 02and between the ends of the insulating ring I00.

The width of the annular groove 9] is substantially equal to theaccumulated thickness of the various elements shown in Fig. :8 whichare'to be assembled in the groove whereby a 'very tight-fit of theelements in the-groove 'is assured. Because of the tight fit requiredbetween the elements and the groove 9|, hand assembly of each individualelement in the groove is "a very diilicult and time-consuming operation.:Since the potentiometer card I or :comprise's a plurality ofturns ofvery fine wire and has-secured thereto very delicate leads I-t5I 05,an-yrelative mova ment'between the insulatingrings I0'I 'or-I0'6 and thecard -I 02 may result in a "serious damage to the windings or leads ofthe potentiometereard. In order to overcome thesedifiiculties it isnecessary to provide a relatively loose preassem'bl-y of the elements ina fixture such as that hereinabove described and transfer the variouselements a's-acomposite unit to the groove '91 of the 130- tentiometerhousing 90.

The various elements to be assembled in the grooveli are firstpositioned in the assembling groove 19 of the fixture 23in-the-followingmanner:

'The bolt I2 is rotated-so as to "allow the spring it to urge the camelupwardly which in turn allows the resilient-clamping'ring B2 to retractto its smallest diameter. When the clamping ring 62 is inthis'retracte'd position, the annular groove IS (Fig. 2) between thebore 25 of the ring '2 and the outer periphery of theclamping ring '62is slightly wider than groove "9| of the potentiometer housing 90."Ili'eslip 'ring '95 is placed "in the'groove I9 with its -"contact"face 97 abutting the "bottomed-of the inner groove 6 t2 Fig. 9) ,andwiththe :o'if-se't :end 96 positioned in the cutout portion 5t! providedon the face of the assembly ring 30 adjacent to thegroove SI. Theintermediate insulating ring 1 00 is then positioned'in the groove 19 sothat it completely surrounds the s'lipring 95 with exception of theoffset end 96 and has its bottom face resting completely on the face ofthe ring 44. The second intermediate insulating ring IOI is positionedin the groove I9 so that it completely surrounds the insulating ring I00and covers the offset end of the slip ring 95, in which case its endsare diametrically opposite the ends 50f the "insulating ring I00.

"The potentiometer card I02 is then positioned in the groove 19 with thebeginning turn I04 directly line with the scribe mark 60 (Fig. 10)provided on the bo'ttom'wall of the sight hole .55 and 'having itscontacting face I-I2 positioned against the bottom '45 of the annulargroove 4| (Fig. 9). The insulating ring I06 is'then positioned in thegroove 1-9 so that it completely surrounds the potentiometer card I02'withth'e exception of the ends of the card on which the leads I 05-I05are secured. The bridge I01 :is placed in the insulating envelope IIOwith its contacting surface I08 extending beyond the sides of theenvelope, and thisunitiispositioned in the groove 19 against the cardand between the ends of the ring I66 so that-its exposed end I-08-engages the recess 5 I provided in the assembly ring opposite the wordbridge scribed on the face of the ring 24.

It will be noted that the slip ring and the potentiometer card I52 arepositioned on the bottom 45 of the annular-grooves El and 42 and therebyhave their contact surfaces 91 and I03, respectively, in thesame :plane,whereas the insulating' -rings I 00, WI and I06 are positioned on theface -of the annular rings 43 and which is substantially above thebottom '45. The bridge I01, however, .is positioned in the recess 51so'that its face I08 abuts the bottom 52 thereof which places the faceof the bridge substantially below thebottom '45 or below the contactingsurface of the slip ring and potentiometer card as senibled in thegroove 19.

As-ea'ch individual element is positioned'in the groove "I9, in-theorder described hereinabove,-its position with respect to the bottom 65of the grooves 4| and 42 or the face of the .:annular rings and 44' isdetermined by'the sight .holes 53-5'3 'and55. For example, when theslipring 95 is positioned in the groove I9, its contacting surface 91must abut the bottomed of .the groove 42. The'sight holes willreadilyindic'at whether or not the slip ring is properly seated .in thegroove 42 around its entire periphery. Likewise, the sight holes willindicate whetheror not the various elements subsequently assembled .inthe fixture groove are-properly positioned on the face of -th ejectorring 36.

-When the various elements have been assembled in the groove I9 asdescribed above, a suitable tool is inserted in the hexagonalaperturei'IZ and'actuated to turn the bolt I2 in a-clockwise directionand draw the cam 68 downwardly against the action of the spring I6.As-the cam 68 1s drawn downwardly, its taperedperipheryengages-thetapered'bore el of the clamping ring 62 'and spreads theperiphery of the clamping ring outwardly against the slip ring 95positioned in the groove 19 andthereby squeezes-theyarious elementspositioned therein tightly together to form a--compos'ite unit. Whenthe-various elearrests ments have been clamped tightly together in thegroove 19, the fixture 23 is removed from the support 30, inverted andpositioned on the face of a potentiometer housing such as the housing9|] (Fig. 11) so that the bottom of the potentiometer card I02 extendsinto the outer groove 9|. The fixture 23 is positioned on the housing sothat the scribe mark 58 provided above the sight.

hole 55 is aligned with a scribe mark I 13 provided on the potentiometerhousing '90. -In this way the beginning turn I04 of the potentiometercard N12 is properly positioned with respect to the potentiometerhousing 90.

When the fixture 23 and the potentiometer housing 90 bear this relationto one another, the two pieces are placed as a unit on a base plate H4of an arbor press (not shown) of standard design and having areciprocable ram H5. The arbor press is actuated so that the ram H isurged downwardly and engages the legs 3T3'l provided on the ejector ring36. As the ram H5 moves downwardly, it causes the ejector ring 3 6 toslide within the fixture 23 and eject the composite unit clamped in thegroove 19 from the fixture 23 into the groove 9| of the housing 90,during which ejection no relative movement occurs between any of theindividual elements of the composite unit being transferred. When theram H5 has descended to th extent that the flange 40 of the ejector ring36 has travelled from the shoulder 38 and abuts the shoulder 21, thecomposite unit has been completely inserted in the groove M (Fig. 12)and the face of the annular rings 43 and 44 is flush with the face ofthe housing 90. The potentiometer card I02 and the slip ring 95 havetheir contacting faces in the same plane and are substantially above thetop face of the various insulating rings I69, I01 and [06. When thevarious elements have been completely transferred from the groove 79 ofthe fixture 23 to the groove 9!, the arbor press is actuated to raisethe ram H5 upwardly whereupon the fixture 23 is removed from th face ofthe potentiometer housing.

It will be noted that the composite unit travels only a relatively shortdistance from the groove 19 when it enters the groove 9i of thepotentiometer housing 91 During the remaining travel of the compositeunit it is dually supported by the fixture groove and the groove 9i ofthe housing 90, whereby the individual elements remain in a tightlyclamped condition during the entire travel of the composite unit. Itwill also be noted that while the composite unit is being ejected fromthe groove 79 by the ejector ring 36, no relative movement can occurbetween the individual elements of the composite unit because eachindividual unit is backed up by the face of the ejector ring. In otherwords, the force applied to the ejector ring by the ram H5 isdistributed equally to each element of the composite unit, whereby thereis no tendency for any individual element thereof to move separately ofthe other elements.

The above-described fixture facilitates a rapid and accurate assembly ofa, potentiometer card and its associated elements in an annular grooveof a potentiometer housing. The fixture provides for a relatively loosepre-assembly of a potentiometer card and associated elements in a grooveprovided therein so that the delicate windings of the card are notdamaged during the preassembly operation. Since no relative movementoccurs between the individual elements of the composit unit during theejection operation, the

potentiometer card winding is further protected from damage.

The fixture 23 is designed to assemble a potentiometer card auditsassociated elements in the outer groove 9| of the potentiometer housing90. In order to assemble a potentiometer card and its associatedelements into the remaining annular grooves 9I-9l, an assembling fixturesimilar to fixture 23 must be used, but of such size that th diameter ofthe assembling groove formed therein is equal to the diameter of theparticular groove of the housing in which the elements are to beassembled. The assembling procedure described hereinabove for fixture 23is followed for each assembling fixture and its respective groove in thehousing 90.

While the above-described invention is particularly well adapted toassemble a potentiometer card and its associated elements into annulargrooves provided in potentiometer housings, it may be readily adapted toassemble a plurality of strip-like elements into a groove of any desiredshape without departing from the spirit and scope of the invention.

What is claimed is:

1. A fixture for assembling potentiometer cards and associatedstrip-like elements in potentiometer housings, which comprises acylindrical body member having a central bore therethrough, a basemember having an annular flange secured to the bottom of said bodymember and a cylindrical body portion extending partially into saidcentral bore, said flange being provided with a plurality of arcuateslots, an annular resilient clamping ring positioned on top of bodyportion of said base so as to form a groove with the central boreprovided in the body member in which a potentiometer card and itsassociated strip-like elements may be assembled in a relatively looseedge-wise position with respect to each other, said resilient ringhaving a tapered bore therethrough, a ring slidably positioned in thelower portion of said central bore and having a plurality of integrallegs which extend through said arcuate slots provided in the flange ofthe base member, the face of said ring being positioned to form thebottom of said groove and having a pair of annular grooves and a pair ofannular rings against which the potentiometer card and its associatedelements are seated when said card and elements are positioned in saidgroove, a plurality of sight holes provided about the periphery of thebody member for viewing the position of the card and elements withrespect to the grooves and rings provided on the face of the ring, a camplate having a tapered periphery in engagement with the tapered bore ofsaid resilient ring, and a stud threadedly mounted in the body portionof the base member and having a flanged head thereon in engagement withsaid cam plate, whereby when the stud is rotated it draws the taperedcam plate into the tapered bore of the resilient ring and expands saidring so as to decrease the width of the groove and clamp thepotentiometer card and associated elements into a composite unit betweenthe central bore and the clamping ring.

2. An apparatus for assembling potentiometer cards and associatedelements in an annular groove provided in a potentiometer housing, whichcomprises a member having an annular groove in which a potentiometercard and its associated insulating elements may be positioned in arelatively loose edge-wise position, said groove having an adjustableinner wall so that means provided on --the --member for *expanding theinner-wall-ofsaid-groove 'so as to clamp the individual elementstogether 'in the groove to form a-composite -unit,-and means provided onthe slidable means-for-effectin'g movement of the slidable means so --as-toe-j ect the composite -unit :from said groove, -whereby'-when saidmember is placed adjacent to a potentiometer housing movement of theslidable means serves to slide the composite unit from the groove in themember into a groove provided in said potentiometer housing.

3. An apparatus for assembling potentiometer cards and associatedstrip-like elements in an annular groove provided in a potentiometerhousing, which comprises a member having an annular groove in which apotentiometer card and its associated strip-like insulating elements maybe assembled in a relatively loose edge-wise position with respect toeach other, said groove having an expandable inner wall so that thewidth of the groove may be decreased after the potentiometer card andthe insulating elements are positioned therein, a slidable memberpositioned in the annular groove so that a face thereof forms a movablebottom for said groove, the face of said slidable member forming thebottom of the groove having means provided thereon for aligning theedges of the potentiometer card and the insulating elements at differentelevations with respect to each other, means provided on the member forexpanding the inner wall of said groove so as to decrease the width ofthe groove and clamp the potentiometer card and its insulating elementstogether in the assembling groove as a composite unit, and meansprovided on the slidable member and projecting externally of the memberwhereby the slidable member may be moved so as to completely eject theclamped composite unit from the groove, whereby when said member isplaced adjacent to a potentiometer housing movement of the slidablemeans serves to slide the composite unit from the groove in the memberinto a groove provided in said potentiometer housing.

4. An apparatus for assembling potentiometer cards and associatedstrip-like elements in an annular groove provided in a potentiometerhousing, which comprises a base having an annular groove therein inwhich a potentiometer card and its associated strip-like elements may beassembled in a relatively loose edge-wise position with respect to eachother, means provided on the base for orientating the potentiometer cardin predetermined position with respect to the base, said groove havingan expandable inner wall so that the width of the groove may bedecreased after the potentiometer card and the associated elements arepositioned therein, an annular member slidably positioned in the grooveso one face thereof forms a movable bottom for said groove, the face ofsaid slidable member forming the bottom of said groove having meansprovided thereon for positioning the edges of the potentiometer card andits associated elements at different elevations with respect to eachother, means for expanding the inner wall of said groove to clamp thepotentiometer card and its associated elements together in theassembling groove as a composite unit, nieans provided on the slidablemember and projecting externally and completely eject the composite unittherefrom; and means provided on the a'nnular member for limiting themovement-ofthe annular movement within said gr-oove, 'wher eby when thebase is positioned over a potentiometer housing so that the orientatingmeans is properly aligned therewith move'men t of the slidable memberserves to slide the composite unit from the groove in the base into agroove provided in the potentiometer housing a predetermined distance.

5. An apparatus for assembling potentiometer cards and associatedelements in an annular groove provided in a potentiometer housing, whichcomprises a base having an annular groove therein in which apotentiometer card and its associated elements may be assembled in arelatively loose edge-wise position with respect to each other, saidgroove having an expandable inner wall, an annular member slidablypositioned in the groove so that one face thereof forms a movable bottomfor said groove, the face of said slidable member forming the bottom ofsaid groove having means provided thereon for positioning the edges ofthe potentiometer card and its associated elements at differentelevations with respect to each other, means provided on the base fordetermining whether the potentiometer card and its associated elementsare properly seated on the bottom of the groove, means for expanding theinner wall of said groove so as to decrease the width of the groove andclamp the potentiometer card and its associated elements together in theassembling groove as a composite unit, and means provided on theslidable member and projecting externally of said base so that theslidable member may be moved to the top of the groove and therebycompletely eject the composite unit therefrom, whereby when said memberis placed adjacent to a potentiometer housing movement of the slidablemeans serves to slide the composite unit from the groove in the memberinto a groove provided in said potentiometer housing.

6. An apparatus for assembling potentiometer cards and associatedstrip-like elements in an annular groove provided in a potentiometerhousing, which comprises a base having an annular groove in which apotentiometer card and its associated strip-like elements may beassembled in a relatively loose edge-wise position with respect to eachother, means provided on the base for orientating one end of thepotentiometer card in a predetermined position in the groove, saidgroove in the base having an expandable inner wall, an annular memberslidably positioned in the groove so that one face thereof forms amovable bottom for said groove, the face of said annular member formingthe bottom of the groove having means provided thereon for positioningthe edges of the potentiometer card and its associated elements atdifferent elevations with respect to each other, means provided on thebase for determining whether the individual elements are properly seatedon the bottom of the groove, means for expanding the inner wall of saidgroove to decrease the width of the groove and clamp the potentiometercard and its associated elements together in the groove as a compositeunit, and means associated with the slidable member and projectingexternally of said base so that the slidable member may be actuated tomove the bottom of the groove to the REFERENCES CITED top of the grooveand thereby eject the composite The following references are of recordin the unit therefrom, whereby when the base is posifile of this patent:

tioned over a potentiometer housing so that the orientating means of thebase is properly aligned 5 UNITED STATES PATENTS with the housingmovement of the slidable mem- Number Name Date ber serves to slide theclamped composite unit 1,128,240 Flint Feb. 9, 1915 from the groove inthe base into the groove pro- 1,135,983 Bartlett Apr. 20, 1915 vided inthe potentiometer housing. 1,661,163 Blomstrom Mar. 6, 1928 10 1,690,322Baker Nov. 6, 1928 BYRON ,P. GIRARD. 2,304,607 Sleeter Dec. 8, 1942BRUNO A, RAETSCH. 2,337,383 Franz Dec. 21, 1943 2,353,774 Wagner July18, 1944:

